Tropical Storm MA-ON Advisory sáb, 12-11

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 27W (MA-ON) WARNING NR
07//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 27W (MA-ON), LOCATED APPROXIMATELY 477 NM
NORTHEAST OF ANDERSEN AFB, GUAM HAS TRACKED WEST-NORTHWESTWARD
AT 08 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL
SATELLITE IMAGERY DEPICTS BUILDING SYMMETRIC CONVECTION OBSCURING A
CONSOLIDATING LOW LEVEL CIRCULATION CENTER (LLCC). AN 110430Z AMSU
89GHZ MICROWAVE IMAGE SHOWS A DEFINED LLCC LOCATED ALONG THE
NORTHWESTERN PERIPHERY OF THE CONVECTION. THE CURRENT POSITION IS
BASED ON THE LLCC IN THE AMSU IMAGE WITH GOOD CONFIDENCE. THE
INTENSITY HAS BEEN KEPT AT 35 KNOTS BASED ON DVORAK INTENSITY
ESTIMATES REMAINING AT T2.5 (35 KNOTS) FROM ALL AGENCIES. TS 27W IS
LOCATED ALONG THE WESTERN AXIS OF AN UPPER LEVEL ANTI-CYCLONE WHERE
ENVIRONMENTAL CONDITIONS ARE MARGINALLY-FAVORABLE. POLEWARD OUTFLOW
IS FAVORABLE AND CURRENTLY OFFSETTING THE LOW TO MODERATE (10-15
KNOT) VERTICAL WIND SHEAR (VWS). TS MA-ON IS TRACKING NORTHWESTWARD
UNDER THE INFLUENCE OF A DEEP LAYERED SUB-TROPICAL RIDGE (STR)
ENTRENCHED TO THE NORTHEAST.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING.
   B. TS MA-ON WILL CONTINUE TRACKING TOWARD THE NORTHWEST UNDER THE
INFLUENCE OF THE STR TO THE NORTHEAST THROUGH THE NEXT 36 HOURS. THE
POLEWARD OUTFLOW WILL CONTINUE TO INCREASE ALLOWING FOR A SLIGHT
INTENSIFICATION TO A PEAK OF 45 KNOTS. AFTERWARDS A MID-LATITUDE
RIDGE PASSING OVER JAPAN WILL CREATE A STRONG LOW-LEVEL NORTHERLY
SURGE WHICH WILL FORCE THE CYCLONE TO TURN SOUTHWESTWARD. THE COLD
AIR ADVECTION AND INCREASED VWS WILL RAPIDLY WEAKEN THE CYCLONE,
FULLY DISSIPATING BY TAU 72 OR POSSIBLY SOONER. DYNAMIC MODEL
GUIDANCE IS IN FAIRLY GOOD AGREEMENT THROUGH TAU 36. BEYOND TAU 36,
SOME MODEL TRACKERS LOSE THE VORTEX SIGNATURE WHICH CREATES A SPREAD
AMONG THE GUIDANCE. HOWEVER, DUE TO THE NEAR TERM AGREEMENT AND
STABLE STEERING SCENARIO, THERE IS HIGH CONFIDENCE IN THE JTWC
FORECAST.//
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